1. Field of the Invention
The present invention generally relates to an antenna and an antenna set, and more particularly, to an antenna and an antenna set adapted for a wireless communication system.
2. Description of Related Art
Currently, people's communication technology has been developed into a new era of wireless communication, in which there are a variety of wireless communication apparatuses developed correspondingly. An antenna is critical component for a wireless communication apparatus which and necessary for receiving signals from a wireless channel. As such, the design of antenna is always an important subject concerned by many research institutes and enterprises in the art.
When a wireless signal is transmitted in the air, a direction of an electric field thereof is usually divided into vertical polarization and horizontal polarization. When the direction of the electric field is perpendicular to the ground plane, the wireless signal is identified as vertical polarized, and when the direction of the electric field is parallel with the ground plane, the wireless signal is identified as horizontal polarized. When a received antenna and an emitted antenna correspond to cross polarization directions, a signal loss will be caused thereby. As such, the received antenna and the emitted antenna must be designed corresponding to a same polarization direction.
The polarization direction of a client end antenna can be either vertical polarization or horizontal polarization. As such, an ordinary wireless fidelity (Wi-Fi) router typically employs a monopole antenna, and configures a movable joint at a terminal thereof. When a base of the monopole antenna is fixed, the monopole antenna can be disposed either vertically or horizontally by adjusting the movable joint. When the monopole antenna is vertically disposed, the polarization direction is vertical polarization, and when the monopole antenna is horizontally disposed, the polarization direction is horizontal polarization. Such an external monopole antenna has the disadvantages of a higher cost, a higher height, and is incapable of being integrated in the wireless product, so that it cannot be designed as an embedded antenna or a hidden antenna.